Pituitary control of erythropoiesis.

Abstract

The effect on erythropoiesis of extracts from human pituitary glands and of single commercially available pituitary hormones has been studied. Extraction of human pituitary glands at pH 3 yielded a material which was erythropoietically active in normal and polycythaemic mice. In hypoxia‐induced polycythaemic mice adrenocorticotropin hydrocortisone, prolactin and TSH increased the 59Fe incorporation into red blood cells. In transfusion‐induced polycythaemic mice, however, only the pituitary extract at pH 3 and prolactin increased the 59Fe uptake. The content of ACTH and TSH in the pituitary extract was measured. ACTH was found in an amount of 1% and TSH less than 2.5%. It is therefore not reasonable that the effect observed is due to a contamination of these hormones only; however, the possibility exists that the erythropoietic effect may be due to a synergistic effect of several hormones. Fractionation of the crude pituitary extract may solve the question of the existence of a specific erythropoietically active pituitary agent.